High-intensity focused ultrasound device and method for controlling piezoelectric driving device used in the same

ABSTRACT

A high-intensity focused ultrasound (HIFU) device and a method for controlling the piezoelectric driving device achieve accurate and stable control as to movement of a transducer and a treatment position by use of a piezoelectric driving device configured to have a compact size in accordance with a great reduction in the size of a handpiece.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a high-intensity focused ultrasound(HIFU) device, which is configured to obtain skin care and anti-agingeffects by focusing high-intensity ultrasound energy on a point of aspecific region in the skin by a transducer, solidifying tissue in thespecific region using high temperature generated at the focal point andregenerating new skin tissue at the solidified tissue, and a method forcontrolling a piezoelectric driving device used in the HIFU device.

Description of the Related Art

Generally, a treatment of forming a solidification zone in a dermislayer of the skin, producing collagen in the solidification zone, tofill the solidification zone, and, as such, obtaining skin care effectssuch as removal of wrinkles is being greatly highlighted. As such atreatment, an invasive method using a microneedle or the like and anon-invasive method using ultrasound or the like are typically used.

For non-invasive treatment, ultrasound is widely used. A medicalappliance using high-intensity focused ultrasound (HIFU), which iscalled an “HIFU device”, has recently been highlighted. For example,such an HIFU device may radiate high-density focused ultrasound intotissue of the skin and, as such, may perform a treatment for skin caresuch as face lifting or skin tightening in a non-invasive manner.

In most cases, HIFU devices generally and widely used for skin care havecommon basic configurations. FIG. 1 shows the configuration of ahandpiece included in a conventional HIFU device.

The handpiece of the conventional HIFU device shown in FIG. 1 includes ahandpiece body 10, and a cartridge 20 as a disposable product detachablycoupled to the handpiece body 10.

A transducer 25, which receives ultrasound energy and focuses thereceived ultrasound energy on a point apart therefrom by a focaldistance, is provided at the cartridge 20. A driver including componentsdesignated by reference numerals 11, etc. should also be provided tolinearly move the transducer 25. In a state in which the cartridge 20 isin contact with the skin, focused ultrasound may be uniformly irradiatedonto the contact portion of the skin in accordance with linear movementof the transducer 25 and, as such, a thermal solidification point may beformed in the skin.

As shown in FIG. 1, the driver includes components provided at thehandpiece body 10, that is, a linear motor 11 and a driving shaft 12.The driver also includes components provided at the cartridge 20, thatis, a connecting shaft 21 connected to the motor driving shaft 12 bymagnets 13 or the like, a fixed member 23 fixed to the connecting shaft21, and a transducer fixing member 24 for fixing the transducer 25 tothe fixed member 23.

The cartridge 20 is not configured to be permanently used after couplingthereof, but is configured to be disposed after a certain number oftreatment times and, as such, to be replaceable with a new one(furthermore, the focal length of the transducer provided at thecartridge is fixed and, as such, various kinds of cartridges havingdifferent focal lengths should be prepared as replaceable cartridges).For this reason, only under the condition that the connecting shaft 21in the cartridge 20 is connected to the driving shaft 12 in thehandpiece body 10 by the magnets 13 or a separate connecting means, canthe connecting shaft 21 receive driving force of the linear motor 11, tomove the transducer 25.

Meanwhile, the cartridge 20 should be filled with certain liquid inorder to enable ultrasound radiation of the transducer 25. In connectionwith this, a bellows 22 should be separately provided to isolate a powertransmission including the connecting shaft 21, etc. in the cartridge 20from the liquid.

As mentioned above, the conventional HIFU device does not employ asystem in which the motor directly drives the transducer disposed in thecartridge, but employs a system in which the motor disposed in thehandpiece body indirectly drives the transducer disposed in thecartridge. Although a DC motor or a stepper motor is typically used as alinear motor for accurate control of the transducer, such a motor has agreat size and, as such, the cartridge should also have a great size foraccommodation of the motor. Furthermore, when the cartridge is scrapped,the motor is scrapped together with the cartridge. With regard to this,the direct drive system in which the motor is disposed in the cartridgeis impractical.

However, the above-mentioned configuration of the conventional HIFUdevice uses the system in which the motor provided at the handpiece bodyindirectly drives the connecting shaft provided at the cartridge and, assuch, may have problems of degraded control accuracy and low stability,as compared to the direct drive system.

Furthermore, since the linear motor moves the driving shaft of the motorforwards and rearwards, spaces for movement of the driving shaft shouldbe secured at front and rear sides of the linear motor. For this reason,it is necessary to increase the length or size of the handpiece bodyand, as such, there may be a problem of a great limitation as tocompactness.

In addition, it is necessary to suppress evaporation of moisture as muchas possible under the condition that the cartridge is filled withliquid. In the cartridge of the above-mentioned conventional HIFUdevice, however, considerable moisture loss through the bellows occursbecause the cartridge should be provided with the power transmissionincluding the connecting shaft to be connected to the driving shaft ofthe motor disposed in the handpiece body, etc. As a result, there may bea problem in that a separate sealing structure or means should beprovided.

As prior art literature associated with the above-mentioned conventionalHIFU device, there are Korean Patent Application Nos. 10-2015-0026533,10-2017-0013457, and 10-2016-0003984.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the aboveproblems, and it is an object of the present invention to provide ahigh-intensity focused ultrasound (HIFU) device capable of achievingaccurate and stable control as to movement of a transducer and atreatment position by use of a piezoelectric driving device configuredto have a compact size in accordance with a great reduction in the sizeof a handpiece, and a method for controlling the piezoelectric drivingdevice.

In accordance with one aspect of the present invention, the above andother objects can be accomplished by the provision of a method forcontrolling a piezoelectric driving device to linearly move a transducerdisposed in a cartridge of a high-intensity focused ultrasoundhandpiece, including: transmitting a high frequency signal to apiezoelectric motor, thereby causing the piezoelectric motor to generatepiezoelectric ultrasound, and causing a piezoelectric driving shaftconnected to the piezoelectric motor to generate vibration in accordancewith the piezoelectric ultrasound, coupling a piezoelectric operatingunit provided with the transducer to the piezoelectric driving shaft,thereby causing the piezoelectric operating unit to move along thepiezoelectric driving shaft in accordance with the vibration of thepiezoelectric driving shaft, and predetermining information as topositions, at which the transducer radiates ultrasound, and performing acontrol operation for stopping the movement of the piezoelectricoperating unit along the piezoelectric driving shaft when it is sensedthat the piezoelectric operating unit reaches one of the predeterminedposition, and irradiating ultrasound through the transducer.

The control operation for stopping the piezoelectric operating unit andirradiating ultrasound through the transducer may include previouslystoring, in association with a position sensor to sense a position ofthe piezoelectric operating unit, sensing values respectivelycorresponding to a plurality of positions, at which the transducerradiates ultrasound, stopping an operation of the piezoelectric motor tostop the piezoelectric operating unit and controlling the transducer toradiate ultrasound when a sensed value of the position sensor generatedduring movement of the piezoelectric operating unit is equal to one ofthe stored sensing values, and repeating the vibration generation, themovement of the piezoelectric operating unit along the piezoelectricdriving shaft, and the ultrasound irradiation through the transducer sothat the transducer sequentially radiates ultrasound at the positionsrespectively corresponding to the stored sensing values.

A magnet may be provided at an end of the piezoelectric operating unit,and a plurality of Hall sensors may be disposed in the cartridge, tosense a magnetic field of the magnet. In this case, the controloperation for stopping the piezoelectric operating unit and irradiatingultrasound through the transducer may include previously storing, inassociation with the Hall sensors, sensing values respectivelycorresponding to a plurality of positions, at which the transducerradiates ultrasound, stopping an operation of the piezoelectric motor tostop the piezoelectric operating unit and controlling the transducer toradiate ultrasound when one of sensed values of the Hall sensorsgenerated during movement of the piezoelectric operating unit is equalto one of the stored sensing values, and repeating the vibrationgeneration, the movement of the piezoelectric operating unit along thepiezoelectric driving shaft, and the ultrasound irradiation through thetransducer so that the transducer sequentially radiates ultrasound atthe positions respectively corresponding to the stored sensing values.

The method may further include moving the piezoelectric operating unitfor a predetermined time after irradiation of ultrasound through thetransducer at a last one of the predetermined positions, moving thepiezoelectric operating unit in an opposite direction, and performing acontrol operation for stopping the movement of the piezoelectricoperating unit along the piezoelectric driving shaft when it is sensedthat the piezoelectric operating unit reaches one of the predeterminedpositions, and irradiating ultrasound through the transducer, whereby adouble shot of ultrasound is carried out at a treatment area through thetransducer.

In accordance with another aspect of the present invention, there isprovided a method for controlling a piezoelectric driving device tolinearly move a transducer disposed in a cartridge of a high-intensityfocused ultrasound handpiece, including transmitting a high frequencysignal to a piezoelectric motor, thereby causing the piezoelectric motorto generate piezoelectric ultrasound, and causing a piezoelectricdriving shaft connected to the piezoelectric motor to generate vibrationin accordance with the piezoelectric ultrasound, coupling apiezoelectric operating unit provided with the transducer to thepiezoelectric driving shaft, thereby causing the piezoelectric operatingunit to move along the piezoelectric driving shaft in accordance withthe vibration of the piezoelectric driving shaft, and performing acontrol operation for sensing light emission or light reception atpositions where the transducer radiates ultrasound, controlling thepiezoelectric operating unit to stop upon sensing the light emission orthe light reception during movement thereof along the piezoelectricdriving shaft, and controlling the transducer to radiate ultrasound.

In accordance with another aspect of the present invention, there isprovided a high-intensity focused ultrasound device for controlling atransducer disposed in a cartridge to linearly move and to radiateultrasound for treatment, including a piezoelectric driving deviceincluding a piezoelectric motor disposed in the cartridge, to generatepiezoelectric ultrasound in accordance with a high frequency signal, apiezoelectric driving shaft connected to the piezoelectric motor, togenerate vibration in accordance with the piezoelectric ultrasound, anda piezoelectric operating unit provided with the transducer and coupledto the piezoelectric driving shaft, to move along the piezoelectricdriving shaft in accordance with the vibration of the piezoelectricdriving shaft, a position sensor for sensing a position of thepiezoelectric operating unit, a high frequency generator for generatinga high frequency signal enabling the piezoelectric motor to generatepiezoelectric ultrasound and a high frequency signal enabling thetransducer to radiate ultrasound for treatment, and a controller forpredetermining information as to positions, at which the transducerradiates ultrasound, and controlling the high frequency generatorperforming a control operation for stopping the movement of thepiezoelectric operating unit along the piezoelectric driving shaft whenit is sensed that the piezoelectric operating unit reaches one of thepredetermined positions, and irradiating ultrasound through thetransducer.

The controller may previously store, in association with the positionsensor, sensing values respectively corresponding to a plurality ofpositions, at which the transducer radiates ultrasound, and may controlthe high frequency generator such that the piezoelectric motor stops andthe transducer radiates ultrasound when a sensed value of the positionsensor generated during movement of the piezoelectric operating unit isequal to one of the stored sensing values.

A magnet may be provided at an end of the piezoelectric operating unit,and a plurality of Hall sensors may be disposed at an area facing themagnet in a movement path of the piezoelectric operating unit within thecartridge while being spaced apart from one another by a predetermineddistance. In this case, the controller may previously store, inassociation with the Hall sensors, sensing values respectivelycorresponding to a plurality of positions, at which the transducerradiates ultrasound, stops an operation of the piezoelectric motor tostop the piezoelectric operating unit and controls the transducer toradiate ultrasound when one of sensed values of the Hall sensorsgenerated during movement of the piezoelectric operating unit is equalto one of the stored sensing values.

The position sensor may include an optical sensor installed at one sideof the piezoelectric driving device, to emit light toward thepiezoelectric operating unit, to receive the light reflected after beingemitted, and to compare the received light with the emitted light,thereby sensing the position of the piezoelectric operating unit.

In accordance with another aspect of the present invention, there isprovided a high-intensity focused ultrasound device for controlling atransducer disposed in a cartridge to linearly move and to radiateultrasound for treatment, including a piezoelectric driving deviceincluding a piezoelectric motor disposed in the cartridge, to generatepiezoelectric ultrasound in accordance with a high frequency signal, apiezoelectric driving shaft connected to the piezoelectric motor, togenerate vibration in accordance with the piezoelectric ultrasound, anda piezoelectric operating unit provided with the transducer and coupledto the piezoelectric driving shaft, to move along the piezoelectricdriving shaft in accordance with the vibration of the piezoelectricdriving shaft, a high frequency generator for generating a highfrequency signal enabling the piezoelectric motor to generatepiezoelectric ultrasound and a high frequency signal enabling thetransducer to radiate ultrasound for treatment, an optical element arrayunit including a first optical element provided at one side of thepiezoelectric operating unit, the first optical element being one of alight emitting element and a light receiving element, and an opticalelement array provided at an area facing the first optical element, theoptical element array including a plurality of second optical elementseach being the other of the light emitting element and the lightreceiving element, so that light reception is achieved between the firstoptical element and the second optical elements during movement of thepiezoelectric operating unit along the piezoelectric driving shaft, anda controller for controlling the high frequency generator to enable thepiezoelectric operating unit to move in accordance with vibrationgenerated by the piezoelectric ultrasound and to enable the transducerto radiate ultrasound, stopping the piezoelectric operating unit whenthe light reception is achieved by the optical element array device, andirradiating ultrasound through the transducer.

In accordance with another aspect of the present invention, there isprovided a high-intensity focused ultrasound device for controlling atransducer disposed in a cartridge to linearly move and to radiateultrasound for treatment, including a piezoelectric driving deviceincluding a piezoelectric motor disposed in the cartridge, to generatepiezoelectric ultrasound in accordance with a high frequency signal, apiezoelectric driving shaft connected to the piezoelectric motor, togenerate vibration in accordance with the piezoelectric ultrasound, anda piezoelectric operating unit provided with the transducer and coupledto the piezoelectric driving shaft, to move along the piezoelectricdriving shaft in accordance with the vibration of the piezoelectricdriving shaft, a high frequency generator for generating a highfrequency signal enabling the piezoelectric motor to generatepiezoelectric ultrasound and a high frequency signal enabling thetransducer to radiate ultrasound for treatment, a light receiving sensorprovided at one side of the piezoelectric operating unit, an opticalslit unit including a sensor housing extending along a movement path ofthe piezoelectric operating unit, a light source disposed in the sensorhousing, and slits formed at positions of the sensor housingcorresponding to positions, at which the transducer radiates ultrasound,respectively, to allow light emitted from the light source to passtherethrough, and a controller for controlling the high frequencygenerator to enable the piezoelectric operating unit to move inaccordance with vibration generated by the piezoelectric ultrasound andto enable the transducer to radiate ultrasound, stopping thepiezoelectric operating unit when the light receiving sensor receiveslight passing through one of the slits of the optical slit unit, andirradiating ultrasound through the transducer.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a view showing a configuration of a conventionalhigh-intensity focused ultrasound (HIFU) device;

FIGS. 2A and 2B are perspective views illustrating the HIFU deviceaccording to an embodiment of the present invention;

FIG. 3 is a schematic view illustrating an inner configuration of theHIFU device illustrated in FIGS. 2A and 2B;

FIG. 4 is an enlarged view illustrating a cartridge of the HIFU deviceaccording to the embodiment of the present invention illustrated in FIG.3;

FIG. 5 is a perspective view of the piezoelectric driving device used inthe HIFU device according to the illustrated embodiment of the presentinvention;

FIG. 6 is an exploded perspective view of the piezoelectric drivingdevice illustrated in FIG. 5;

FIG. 7 is an exploded perspective view of a piezoelectric operating unitillustrated in FIG. 6′

FIG. 8 is a view explaining operation of the HIFU device according tothe illustrated embodiment of the present invention;

FIG. 9 is a schematic view explaining a method for controlling apiezoelectric operating unit and a transducer in a piezoelectric drivingdevice used in the HIFU device in accordance with an embodiment of thepresent invention; and

FIGS. 10 to 12 are schematic views explaining methods for controlling apiezoelectric operating unit and a transducer in a piezoelectric drivingdevice used in the HIFU device in accordance with various embodiments ofthe present invention, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, concrete contents of a high-intensity focused ultrasound(HIFU) device according to the present invention and a method forcontrolling a piezoelectric driving device used in the HIFU device inaccordance with the present invention will be described with referenceto the accompanying drawings.

First, an HIFU device according to an embodiment of the presentinvention will be described with reference to FIGS. 2A, 2B and 3. FIGS.2A and 2B are perspective views of the HIFU device according to theillustrated embodiment of the present invention. FIG. 3 is a schematicview illustrating an inner configuration of the HIFU device illustratedin FIGS. 2A and 2B.

As illustrated in FIGS. 2A, 2B and 3, the HIFU device according to theillustrated embodiment of the present invention includes a handpiecebody 100, a cartridge 200, and a piezoelectric driver (300) disposed inthe cartridge 200.

FIG. 2A shows a state of the HIFU device according to the illustratedembodiment in which the cartridge 200 is coupled to the handpiece body100. FIG. 2B shows a state in which the cartridge 200 is separated fromthe handpiece body 100.

The HIFU device may be configured to be connected to a separateappliance body (not shown) in a wired manner and to operate in awireless manner without being connected to the separate appliance body.

In FIGS. 2A and 2B, reference numeral “212” designates a contact headwhich is a portion of the cartridge 200 to contact the skin of a personto be treated (hereinafter simply referred to as a “patient”), referencenumeral “210” designates a body of the cartridge 200, reference numeral“211” designates a handpiece coupling section, and reference numeral“102” designates a cartridge coupling section.

As illustrated in FIGS. 2A and 2B, when the handpiece coupling section211, which is provided at the cartridge body 210 of the cartridge 200,is coupled to the cartridge coupling section 102, which is provided at afront portion of the handpiece body 100, a printed circuit board (PCB)provided at the cartridge 200 is electrically connected to a controllerprovided at the handpiece body 100 and, as such, a transducer disposedin the cartridge 200 may perform irradiation with ultrasound whilemoving under control of the controller.

The HIFU device according to the illustrated embodiment of the presentinvention has no connection configuration, except for electricalconnection between the cartridge 200 and the handpiece body 100. Thatis, in the HIFU device, there is no power connection configuration as inthe configuration of the conventional HIFU device in which the shaft ofthe cartridge is connected to the driving shaft of the driving device.

As illustrated in FIG. 3, the handpiece body 100 includes an ultrasoundgenerator 120 disposed in the handpiece body 100, and a controller 110disposed in the handpiece body 100, to control generation of anultrasound signal from the ultrasound generator 120.

In the HIFU device according to the present invention, constituentcomponents such as a linear motor and a motor driving shaft are notdisposed in the handpiece body 100 and, as such, considerable extraspace may be secured in the handpiece body 100. Accordingly, theultrasound generator 120 and the controller 110 for controlling theultrasound generator 120, which are difficult to provide at thehandpiece of the conventional HIFU device (thus, inevitably beingprovided at the body) may be installed in the handpiece body 100, and,as such, the HIFU device according to the present invention has afeature in that the size of the body may be greatly reduced or theappliance body itself may be eliminated, and, at the same time, thehandpiece may be further compacted.

Hereinafter, more concrete configurations of the above-describedcartridge and piezoelectric driving device will be described withreference to FIG. 4. FIG. 4 shows, in an enlarged state, the cartridgeof the HIFU device according to the embodiment of the present inventionillustrated in FIG. 3.

As illustrated in FIG. 4, the cartridge 200 of the HIFU device accordingto the illustrated embodiment of the present invention includes thecartridge body 210, which is filled with a fluid W for generation ofultrasound, and the contact head 212, which is to closely contact theskin of a patient. The contact head 212 is disposed at one side of thecartridge body 210. The cartridge 200 also includes a PCB 220 disposedat an outer surface of the cartridge body 210.

The piezoelectric driving device 300, which functions as a driving meansfor driving a transducer 380, to move the transducer 380, is disposed inthe cartridge body 210, together with the transducer 380. Thepiezoelectric driving device 300 and the transducer 380 are dipped inthe fluid W filling the cartridge body 210.

The cartridge body 210 is configured to substantially completely sealthe interior thereof in order to prevent the fluid W from being lost dueto evaporation or the like. In connection with this, the cartridge ofthe conventional HIFU device has a configuration in which fluid loss mayeasily occur, because the cartridge has a power connection configurationto be connected to the motor provided at the handpiece body. On thecontrary, the cartridge 200 of the HIFU device according to theillustrated embodiment of the present invention has a feature in thatthe interior of the cartridge 200 is substantially completely sealedand, as such, there is no or little substantial fluid loss of thecartridge 200.

As illustrated in FIG. 4, the piezoelectric driving device according tothe illustrated embodiment of the present invention uses a piezoelectricmotor as a driving unit in order to enable the piezoelectric drivingdevice to operate in a state of being dipped in the fluid W contained inthe cartridge body 210.

The piezoelectric motor has an advantage in that the piezoelectric motoruses a considerably low driving voltage, as compared to conventionallinear motors or DC motors, while being manufactured to have a verysmall size.

Such a piezoelectric motor has also been used in conventional cases.However, the inventors have developed a piezoelectric driving devicecapable of exhibiting suitable performance in an HIFU device through useof a piezoelectric motor, after conducting active research intoapplication of a piezoelectric motor to an HIFU device. The presentinvention provides a piezoelectric driving device capable of accuratelycontrolling movement of a transducer through an operation according todriving force of a piezoelectric motor, even though the piezoelectricdriving device is dipped in a fluid contained in a cartridge body.

As illustrated in FIGS. 3 and 4, the piezoelectric driving device 300includes a driving frame 310 fixed to one side of the cartridge body 210within the cartridge body 210, a piezoelectric driving unit 330 forgenerating driving force using ultrasound generated in accordance with ahigh frequency signal from the high frequency generator 120, and apiezoelectric operating unit 350 for moving the transducer 380 whilebeing moved by the driving force generated from the piezoelectricdriving unit 330.

The piezoelectric operating unit 350, to which the transducer 380 iscoupled, moves along a piezoelectric driving shaft 341 of thepiezoelectric driving unit 330 in accordance with vibration of thepiezoelectric driving shaft 341.

A concrete configuration of the piezoelectric driving device 300 will bedescribed later.

Meanwhile, the above-described piezoelectric driving device 300 isconfigured to be driven in the fluid W contained in the cartridge body210, as illustrated in FIGS. 3 and 4. In connection with this, thecartridge body 210 is configured to be substantially sealed in order toprevent loss of the fluid W contained therein.

As illustrated in FIG. 4, the PCB 220 is disposed at an outer topsurface of the cartridge body 210. The connector 224 is provided at anexposed end of the PCB 220. When the cartridge 200 is coupled to thehandpiece body 100, the connector 224 is coupled to a contact 112provided at the handpiece body 100 and, as such, electrical connectionmay be achieved.

As illustrated in FIGS. 3 and 4, the piezoelectric driving device 300 isdisposed in the cartridge body 210 in a fixed state. The PCB 220, whichis disposed adjacent to the piezoelectric driving device 300 outside thecartridge body 210, is electrically connected to the piezoelectricdriving device 300 via electric wires. In this case, the electric wiresmay be treated by a sealing process in order to maintain the interior ofthe cartridge body 210 in a sealed state.

The piezoelectric driving unit 330 of the piezoelectric driving device300 and the transducer 380 are electrically connected to the PCB 220 bysealed electric wires and, as such, are connected to the controller 110disposed in the handpiece body 100 when the connector 224 is connectedto the contact 112 in accordance with coupling of the cartridge 200 tothe handpiece body 100. In this state, the controller 110 may transmit ahigh frequency signal for generation of high-intensity focusedultrasound to be irradiated by the transducer 380 and a high frequencysignal for generation of ultrasound vibration as driving force of thepiezoelectric driving unit 330 while controlling the high frequencygenerator 120. The PCB 220 may transfer respective signals to thetransducer 380 and the piezoelectric driving unit 330 via associatedones of the electric wires.

As high frequency signals generated from the high frequency generator120 are transmitted to the transducer 380 and the piezoelectric drivingunit 330, respectively, under control of the controller 110, asdescribed above, the transducer 380 transmits ultrasound energy to aspecific position in the skin through radiation of high-intensityfocused ultrasound according to a focal length of a piezoelectricceramic disposed in the transducer 380, and, at the same time, thepiezoelectric driving unit 330 generates ultrasound vibration inaccordance with the associated high frequency signal and, as such, movesthe piezoelectric operating unit 350, thereby causing the transducer 380to move.

In this case, the contact head 212 of the cartridge 200 is open at abottom portion thereof, and the open portion is sealed by a film 214made of a specific material. When the skin of a patient is subjected toultrasound treatment, ultrasound energy radiated through the transducer380 passes through the film 214 under the condition that the portion ofthe contact head 212 corresponding to the film 214 is in contact withthe skin, and is then transferred to tissue present at a focal distancein the skin.

Meanwhile, as illustrated in FIG. 4, the magnet 355 is fixed to an endof the piezoelectric operating unit 350 in the piezoelectric drivingdevice 300, and magnetic field sensors such as the Hall sensors 222provided at the PCB 220 are arranged in plural at an area facing themagnet 355 while being uniformly spaced apart from one another by apredetermined distance. As the piezoelectric operating unit 350 movesthe transducer 380 in accordance with driving force of the piezoelectricdriving unit 330, the magnet 355 moves. At this time, the Hall sensors222 on the PCB 220 sense a magnetic field of the magnet 355 and, assuch, sense and trace movement of the piezoelectric operating unit 350,that is, movement of the transducer 380 (a signal sensed by each Hallsensor 222 is transmitted to the controller 110 and, as such, thecontroller 110 obtains information as to sensed and traced movement ofthe transducer 380, and controls generation of a high frequency signalbased on the obtained information).

Meanwhile, a concrete configuration of the piezoelectric driving device300 according to the illustrated embodiment of the present inventionwill be described with reference to FIGS. 5 to 7.

FIG. 5 illustrates a perspective view of the piezoelectric drivingdevice 300 according to the illustrated embodiment of the presentinvention. FIG. 6 illustrates an exploded perspective view of thepiezoelectric driving device illustrated in FIG. 5. FIG. 7 illustratesan exploded perspective view of the piezoelectric operating unitillustrated in FIG. 6.

As illustrated in FIGS. 5 and 6, the piezoelectric driving device 300according to the illustrated embodiment of the present invention mayinclude the driving frame 310, the piezoelectric driving unit 330, andthe piezoelectric operating unit 350.

As illustrated in FIGS. 5 and 6, the driving frame 310 may include aframe body 311, a driving unit coupling/support member 313 provided atone side of the frame body 311, and an operation support member 314provided at the other side of the frame body 311. The driving frame 310may also include first and second guide shafts 321 and 322, each ofwhich has one end fixed to the driving unit coupling/support member 313and the other end fixed to the operation support member 314.

As illustrated in FIG. 6, a body coupling hole 313 a and engagementholes 313 b may be provided at the driving unit coupling/support member313. The piezoelectric driving unit 330 is primarily coupled to the bodycoupling hole 313 a, and is secondarily engaged with the engagementholes 313 b. Accordingly, the piezoelectric driving unit 330 may befirmly coupled to the driving unit coupling/support member 313.

Meanwhile, as illustrated in FIGS. 5 and 6, the piezoelectric drivingmember 330 includes a piezoelectric motor (not shown) for generatingpiezoelectric ultrasound in accordance with a high frequency signal fromthe ultrasound generator 120 (FIG. 3) provided at the handpiece body,and a driving unit coupling body 331 coupled to the driving unitcoupling/support member 313 while accommodating the piezoelectric motor.The piezoelectric motor is received in the driving unit coupling body331 and, as such, is not visible in FIGS. 5 and 6.

As the piezoelectric motor of the piezoelectric driving unit 330generates ultrasound vibration in a state in which the piezoelectricdriving unit 330 is coupled to the driving unit coupling/support member313, the vibration is transmitted to the entirety of the driving frame310. In connection with this, an intermediate space A is formed at aportion of the driving unit coupling/support member 313, to more or lessattenuate vibration transmitted to the entirety of the driving frame310. It may also be possible to more or less absorb vibrationtransmitted to the driving frame 310 by providing a member made of avibration absorbing material at the intermediate space A.

The piezoelectric motor disposed in the driving unit coupling body 331may be provided with a piezoelectric driving shaft 314. Thepiezoelectric driving shaft 314 is connected, at one end thereof, to thepiezoelectric motor and, as such, generates vibration in accordance withpiezoelectric ultrasound from the piezoelectric motor. When the drivingunit coupling body 331 is coupled to the driving unit coupling/supportmember 313, the other end of the piezoelectric driving shaft 314 isfixed to the operation support member 314.

A body coupling portion 332 and slide-fit engagement portions 333 areprovided at one side of the driving unit coupling body 331. The bodycoupling portion 332 may be coupled to the body coupling hole 313 a ofthe driving unit coupling/support member 313 in a tight fit manner. Atthe same time, the slide-fit engagement portions 333 may be firmlyengaged with the engagement holes 313 b in a slide-fit manner.

Meanwhile, as illustrated in FIGS. 5 and 6, the piezoelectric operatingunit 350 is coupled to the piezoelectric driving shaft 341 such that thepiezoelectric operating unit 350 is movable along the piezoelectricdriving shaft 341 in accordance with vibration of the piezoelectricdriving shaft 341 and, as such, the transducer 380 coupled to thepiezoelectric operating unit 350 is movable.

As illustrated in FIGS. 6 and 7, the piezoelectric operating unit 350may include an operating body 352, a transducer coupling member 351provided at the operating body 352 and coupled with the transducer 380,and a driving core member 360 surrounding the piezoelectric drivingshaft 341 while being received in a core receiving portion 353 formed atthe operating body 352. The driving core member 360 is movable along thepiezoelectric driving shaft 341 in accordance with vibration of thepiezoelectric driving shaft 341.

The transducer coupling member 351 may be disposed at one end of theoperating body 352 and, as such, the transducer 380 may be coupled tothe operating body 352. A column member 354 may be provided at the otherend of the operating body 352, to receive the magnet 355 as describedabove.

The driving core member 360 disposed in the core receiving portion 353of the piezoelectric operating unit 350 may include a first driving core361 disposed in one side of the core receiving portion 353 of theoperating body 352 and provided with a groove h1 corresponding to thepiezoelectric driving shaft 341, and a second driving core 362 disposedin the other side of the core receiving portion 353, to face the firstdriving core 361, and provided with a groove h2 corresponding to thepiezoelectric driving shaft 341. The driving core member 360 may alsoinclude an elastic support ring 363 for elastically supporting a statein which the piezoelectric driving shaft 341 is fitted in a hole Hformed by the groove h1 of the first driving core 361 and the groove h2of the second driving core 362.

The first and second driving cores 361 and 362 may be made of specificmetal. The piezoelectric driving shaft 341 may extend through the hole Hformed by the grooves h1 and h2 of the first and second driving cores361 and 362 without being tightly fitted in the hole H, that is, underthe condition in which a micro-gap is formed between the piezoelectricdriving shaft 341 and the hole H.

As a micro-gap is present between the hole H and the piezoelectricdriving shaft 341, ultrasound vibration generated from the piezoelectricdriving shaft 341 is transmitted to the driving core unit 360 and, assuch, the piezoelectric operating unit 350 may move in accordance withthe transmitted vibration.

In this case, movement of the piezoelectric operating unit 350 may beadjusted as the frequency of a frequency signal generated from the highfrequency generator 120 is controlled by the controller 110 (FIG. 3).

The controller 110 may control the transducer to move at an appropriatespeed by appropriately controlling the frequency of the frequency signalin accordance with operation of the user to manipulate the device orsensing of a position of the transducer.

As illustrated in FIG. 7, a first support groove sh1 is formed at thefirst driving core 361, and a second support groove sh2 is formed at thesecond driving core 362. The elastic support ring 363 is received in thefirst and second support grooves sh1 and sh2 under the condition thatthe first and second driving cores 361 and 362 are in contact with eachother to form the hole H and, as such, the elastic support ring 363elastically supports the contact state of the first and second drivingcores 361 and 362.

As elastic support of the first and second driving cores 361 and 362 isachieved by the elastic support ring 363, as described above, vibrationof the piezoelectric driving shaft 341 may be reliably transmitted tothe first and second driving cores 361 and 362 and, as such, thepiezoelectric operating unit 350 may be easily movable.

In addition, as illustrated in FIG. 7, a core support cover 356 may beprovided to support a state in which the driving core unit 360 isreceived in the core receiving portion 353 of the operating body 352 inthe piezoelectric operating unit 350. When the core support cover 356 iscoupled to the operating body 352 in a state in which the driving coreunit 360 is received in the core receiving portion 353, the core supportcover 356 supports the received state of the driving core unit 360.

Meanwhile, as illustrated in FIGS. 5 to 7, the piezoelectric drivingdevice according to the illustrated embodiment of the present inventionmay include a first slide groove 371 provided at one side of theoperating body 352 of the piezoelectric operating unit 350 and a secondslide groove 372 at the other side of the operating body 352. The firstslide groove 371 is fitted around the first guide shaft 321, and thesecond slide groove 372 is fitted around the second guide shaft 372.When the piezoelectric operating unit 350 is moved by the piezoelectricdriving shaft 341 and the driving core unit 360, the piezoelectricoperating unit 350 is guided by the first guide shaft 321 fitted in thefirst slide groove 371 and the second guide shaft 322 fitted in thesecond slide groove 372 and, as such, stable movement of thepiezoelectric operating unit 350 may be achieved.

If the piezoelectric operating unit 350 moves in a state in which thefirst and second guide shafts 321 and 322 are fitted in holes,respectively, in place of the first and second slide grooves 371 and372, there may be a problem in that movement of the piezoelectricoperating unit 350 may be inefficiently carried out due to frictiongenerated between each of the guide shafts 321 and 322 and theassociated hole. To this end, in the piezoelectric driving deviceaccording to the illustrated embodiment of the present invention, eachof the first and second slide grooves 371 and 372 in the piezoelectricoperating unit 350 is formed to be open at one side and, as such, tosubstantially have a 90°-rotated U shape. As the guide shafts 321 and322 are fitted in the first and second slide grooves 371 and 372 formedas described above, respectively, there may be a feature in thatmovement of the piezoelectric operating unit 350 is smoothly and stablyguided without friction.

Hereinafter, operation of the piezoelectric driving device having theabove-described configuration according to the illustrated embodiment ofthe present invention and operation of the HIFU device using thepiezoelectric driving device will be described with reference to FIG. 8.

The transducer 380 coupled to the piezoelectric driving device 300disposed in the cartridge 200 is a kernel component of the HIFU device.The focal distance of ultrasound varies in accordance with the curvatureand installation position of the piezoelectric ceramic disposed in thetransducer 380 and, as such, the treatment depth of the skin tissue(treatment area or position) by the ultrasound varies.

Once the piezoelectric ceramic is installed in the transducer 380, thefocal length of the piezoelectric ceramic is fixed and, as such, thetreatment depth is fixed. The kind of the piezoelectric ceramic (thecurvature of the piezoelectric ceramic) and the installation position ofthe piezoelectric ceramic are determined in accordance with which one ofan SMAS layer, a muscle layer and a dermis layer in the skin isdetermined as a treatment area. Accordingly, cartridges respectivelyprovided with transducers suitable for different treatment areas areprepared and, as such, a selected one of the cartridges meeting aselected treatment area may be used under the condition that theselected cartridge is coupled to the handpiece body.

Information as to the focal length of the transducer or the treatmentdepth (information previously determined in accordance with theinstallation position of the piezoelectric ceramic in the transducer) isstored in a memory (not shown) provided at the PCB 220. Information asto the frequency of a high frequency signal for generation of ultrasoundto be radiated through the transducer and information as to thefrequency of a high frequency signal for driving of the piezoelectricmotor may also be previously stored in the memory.

Accordingly, when the cartridge 200 is coupled to the handpiece body100, the connector 224 is connected to the contact 112 and, as such,electrical connection between the cartridge 200 and the handpiece body100 is achieved. In this state, the above-described information storedin the memory of the PCB 220 is transmitted to the controller 110 of thehandpiece body 100. Accordingly, the controller 110 controls signalsgenerated from the high frequency generator 120 in accordance with thetransmitted information and, as such, controls generation of ultrasoundfrom the transducer 380 and the piezoelectric motor.

When a thermal solidification point is formed at a predetermined depthin accordance with ultrasound energy generated through transmission of ahigh frequency signal to the transducer 380 under control of thecontroller 110 under the condition that the contact head 212 of thecartridge 200 is closely in contact with the skin, the controller 110controls a high frequency signal transmitted to the piezoelectricdriving unit 330, to move the piezoelectric operating unit 350 and, assuch, to move the transducer 380. In accordance with movement of thetransducer 380, a thermal solidification point is formed at the nextposition in the same manner as described above.

In such a manner, a plurality of uniformly spaced thermal solidificationpoints CA is created in a treatment area in the skin tissue and, assuch, treatment is completed. Collagen is produced or tightening isachieved at the thermal solidification points during a self-healingprocedure after the treatment and, as such, skin lifting effects may beobtained.

Meanwhile, as illustrated in FIG. 8, it is necessary to form thermalsolidification points CA at a uniform interval a in an area of the skinthrough radiation of ultrasound by the transducer 380. To this end, thecontroller 110 controls a high frequency signal generated from the highfrequency generator 120, to stop the piezoelectric operating unit 350after moving the piezoelectric operating unit 350 by a distancecorresponding to the interval a, to form a thermal solidification pointthrough radiation of high-intensity focused ultrasound from thetransducer 380 onto a point in the skin corresponding to the focallength of the transducer, to again move the piezoelectric operating unit350 by the distance corresponding to the interval a, and then to repeatthe above operations. Thus, a plurality of thermal solidification pointsCA having a uniform interval a may be formed, as illustrated in FIG. 8.

Hereinafter, a control method for accurately controlling movement of thepiezoelectric operating unit through the piezoelectric motor of thepiezoelectric driving device in order to form a plurality of thermalsolidification points having the above-described uniform interval willbe described with reference to FIGS. 9 to 12.

FIGS. 9 to 12 illustrate various embodiments associated with theabove-described piezoelectric driving device control method. In FIGS. 9to 12, constituent components are simply illustrated for explanation ofcontrol as to movement of the piezoelectric operating unit in thepiezoelectric driving device.

First, the HIFU device according to the illustrated embodiment and themethod for controlling the piezoelectric driving device used in the HIFUdevice will be described with reference to FIG. 9.

As illustrated in FIG. 9, in the piezoelectric driving device of theHIFU device according to the illustrated embodiment of the presentinvention, the piezoelectric motor 330 generates piezoelectricultrasound under control of the controller 110 and, as such, thepiezoelectric driving shaft 341 vibrates. In accordance with thevibration, the piezoelectric operating unit 350 moves along thepiezoelectric driving shaft 341 in an arrow direction. The transducer380 is disposed at an end of the piezoelectric operating unit 350opposite to the magnet 355.

The piezoelectric operating unit 350 moves from a start position Ps, andthen stops at a position P1. At the position P1, the piezoelectricoperating unit 350 allows the transducer 380 to irradiate ultrasoundonto the skin in order to form a thermal solidification point, and thenagain moves to a position P2. At the position P2, the piezoelectricoperating unit 350 allows the transducer 380 to irradiate ultrasoundonto the skin in a stopped state, thereby forming another thermalsolidification point. In such a manner, the piezoelectric operating unit350 moves up to an arrival position Pe through repeated movement andstops at intervals of a distance d while sequentially allowing thetransducer 380 to radiate ultrasound to positions P1 to P8. In thiscase, the interval of the positions P1 to P8 should be substantiallyequal to the distance d.

Movement of the piezoelectric operating unit 350 at intervals of thedistance d as described above may be possible in accordance with controlof the frequency and pulses of the high frequency signal transmitted tothe piezoelectric motor 330 by the controller 110.

That is, the controller 110 controls the frequency of the high frequencysignal transmitted to the piezoelectric motor 330 for movement of thepiezoelectric operating unit 350 such that the frequency of the highfrequency signal becomes constant, and predetermines the number ofpulses required for movement of the piezoelectric operating unit 350 bythe distance d.

When the controller 110 applies the predetermined number of pulses tothe piezoelectric motor 330, the piezoelectric operating unit 350 movesthe distance d, and then stops. At this time, the controller 110transmits a high frequency signal for radiation of ultrasound to thetransducer 380, to form a thermal solidification point in an area of theskin. As the above control is repeated, the piezoelectric operating unit350 may stop at each of the positions P1 to P8 after interval movementthereof and may then allow the transducer 380 to radiate ultrasound inthe stopped state.

For example, when 120 pulses at a frequency of 50 kHz are applied formovement of the piezoelectric operating unit 350 at intervals of thedistance d, the controller 110 transmits a signal of 50 kHz and 120pulses to the piezoelectric motor 330, and then transmits a highfrequency signal to the transducer 380 for radiation of ultrasound. Asthe above operation is repeated, thermal solidification points having auniform interval may be formed at the positions P1 to P8, respectively.Although FIG. 9 illustrates an example in which the transducerirradiates 8 points P1 to P8 with ultrasound, the present invention isnot limited thereto. How many points are to be subjected to irradiationwith ultrasound is arbitrary.

Meanwhile, although the same number of pulses is applied, thepiezoelectric operating unit 350 may not always move the distance dbecause the piezoelectric motor 330 is connected to one end of thepiezoelectric driving shaft 341.

For example, although the piezoelectric operating unit 350 correctlymoves from the position Ps to the position P1 by the distance d inaccordance with the signal of 120 pulses, the piezoelectric operatingunit 350 may not move the distance d in accordance with the signal of120 pulses when moving from the position P3 to the position P4. In thiscase, the piezoelectric operating unit 350 may not correctly stop at theposition P4. Such a phenomenon may become more severe as movement of thepiezoelectric operating unit 350 is continued.

To this end, numbers of pulses required for respective movements of thepiezoelectric operating unit 350 among Ps, P1, P2, . . . , P8, and Pemay be measured, and pulse signals having respective measured numbers ofpulses may be applied for respective movements of the piezoelectricoperation unit 350, and as such, the piezoelectric operating unit 350may accurately move a distance substantially equal to the distance d.

Meanwhile, an HIFU device according to another embodiment of the presentinvention and a method for controlling a piezoelectric driving deviceused in the HIFU device will be described with reference to FIG. 10.

The embodiment illustrated in FIG. 9 relates to the method forcontrolling movement of the piezoelectric operating unit in accordancewith control of the frequency and pulses of a high frequency signaltransmitted to the piezoelectric motor, and, in connection with this,the problem of a difficulty in accurate control has been described.

The embodiment illustrated in FIG. 10 provides a control method for moreaccurate and stable movement of the piezoelectric operating unit capableof eliminating the problem encountered in the embodiment illustrated inFIG. 9.

That is, the embodiment illustrated in FIG. 10 provides a control methodin which a position of the piezoelectric operating unit shifted inaccordance with the piezoelectric operating unit is sensed by a positionsensor provided at the piezoelectric driving device, and, based on asensed value, the piezoelectric operating unit stops at a correspondingone of the positions P1 to P8, and allows radiation of ultrasound at thestopped position.

Matters associated with positions, at which the transducer 380 radiatesultrasound between the start point Ps and the arrival position Pe, thatis, P1 to P8, in FIG. 10 are the same as those of FIG. 9, and, as such,no description thereof will be given.

In the control method for the piezoelectric driving device according tothis embodiment, the controller 110 performs a control process of:transmitting a high frequency signal to the piezoelectric motor 330 suchthat the piezoelectric motor 330 generates piezoelectric ultrasound, thepiezoelectric driving shaft 341 connected to the piezoelectric motor 330generates vibration according to the generated piezoelectric ultrasound,and the piezoelectric operating unit 350 coupled to the piezoelectricdriving shaft 341 moves along the piezoelectric driving shaft 341 inaccordance with the vibration of the piezoelectric driving shaft 341;predetermining information as to positions P1 to P8, at which thetransducer 380 radiates ultrasound; and controlling the piezoelectricoperating unit 350 and the transducer 380 such that, every time it issensed that the piezoelectric operating unit 350 reaches one of thepredetermined positions P1 to P8 after movement thereof along thepiezoelectric driving shaft 341, the piezoelectric operating unit 350stops, and the transducer 380 is enabled to radiate ultrasound. Themovement and stop of the piezoelectric operating unit 350 (at the sametime, ultrasound radiation through the transducer 380) are repeated fromthe predetermined position P1 to the predetermined position P8.

Here, the control to stop the piezoelectric operating unit and then toirradiate ultrasound through the transducer is a control process inwhich, in association with the position sensor to sense a position ofthe piezoelectric operating unit 350, the controller 110 predeterminesor stores sensing values corresponding to respective positions P1 to P8and, as such, the controller 110 stops operation of the piezoelectricmotor 330 to stop the piezoelectric operating unit 350 and controls thetransducer 380 to radiate ultrasound when a sensed value of the positionsensor generated during movement of the piezoelectric operating unit 350along the piezoelectric driving shaft 341 is equal to one of the storedsensing values. The above-described process is repeatedly carried out atthe previously stored plural positions P1 to P8.

In more detail, as illustrated in FIG. 10(a), in the configuration inwhich the magnet 355 is provided at an end of the piezoelectricoperating unit 350, and a plurality of Hall sensors 222 is provided atthe PCB 220 disposed in the cartridge, to sense a magnetic field of themagnet 355, sensing values of the Hall sensors 222 at respectivepositions P1 to P8 are previously stored (the controller may storeInformation as to the sensing values therein or may download theinformation from the PCB, which stores the information in the memorythereof).

The controller 110 transmits a high frequency signal to thepiezoelectric motor 330, to move the piezoelectric operating unit 350 inan arrow direction shown in FIG. 10(a). When the controller 110determines a value sensed by one of the Hall sensors 222 during movementof the piezoelectric operating unit 350 to be equal to one of the storedsensing values, the controller 110 stops operation of the piezoelectricmotor 330 and, as such, the piezoelectric operating unit 350 stops. Atthe same time, the controller 110 controls the transducer 380 to radiateultrasound and, as such, a thermal solidification point CA is formed inan area of the skin. In such a manner, the value sensed for each of thepredetermined positions P1 to P8 is compared with the stored sensingvalues, and ultrasound is radiated from the transducer 380 when thesensed value is equal to one of the stored sensing values, and, as such,thermal solidification points CA may be formed at intervals of thedistance d at the positions P1 to P8, respectively.

Meanwhile, after radiation of ultrasound from the transducer 380 at afinal one of the predetermined positions P1 to P8, that is, the positionP8, the piezoelectric operating unit 350 is moved for a predeterminedtime, to be positioned at the arrival position Pe, and, as such,formation of a series of thermal solidification points is completed.Here, the arrival position Pe may not be a position spaced apart fromthe position P8 by the distance d, but may be a position at which thepiezoelectric operating unit 350 is positioned after moving for apredetermined time.

A double shot may proceed to again form thermal solidification points atthe positions where a series of thermal solidification points has beenformed, respectively. This process may be achieved by performingradiation of ultrasound from the position P8 to the position P1 in areverse order while moving the piezoelectric operating unit 350 from theposition Pe in an opposite direction.

Meanwhile, an HIFU device according to another embodiment of the presentinvention and a method for controlling a piezoelectric driving deviceused in the HIFU device will be described with reference to FIG. 11.

Similarly to the embodiment of FIG. 10, the embodiment illustrated inFIG. 11 provides a control method for more accurate and stable movementof the piezoelectric operating unit capable of eliminating the problemencountered in the embodiment illustrated in FIG. 9.

The embodiment of FIG. 11 relates to a configuration in which an opticalelement array unit is provided at the piezoelectric driving device. Inthis case, the optical element array unit basically uses a first opticalelement, which is one of a light emitting element and a light receivingelement, and a second optical element, which is the other of the lightemitting element and the light receiving element. In detail, a firstlight element 358 is provided at one side of the piezoelectric operatingunit 350, and an optical element array 225 including a plurality ofsecond optical elements 225 a is provided at an area facing the firstoptical element 358, and, as such, light reception is achieved betweenthe first optical element 358 and one of the second optical elements 225a during movement of the piezoelectric operating unit 350 along thepiezoelectric driving shaft 341.

FIG. 11(a) illustrates an example in which the optical element array 225is constituted by a plurality of uniformly-spaced light emittingelements 225 a arranged on the PCB 220, and a light receiving element isprovided, as the optical element 358, at an end of the piezoelectricoperating unit 350, to receive light from the light emitting elements225 a. On the contrary, the optical element array 225 may be embodied bya plurality of light receiving elements, and a light emitting elementmay be provided at the end of the piezoelectric operating unit 350.

As illustrated in FIG. 11(a), the light emitting elements 225 aconstituting the optical element array 225 may be provided at positionscorresponding to the positions P1 to P8, at which the transducer 380radiates ultrasound, respectively.

In the control method for the piezoelectric driving device according tothis embodiment, as illustrated in FIG. 11(b), the controller 110performs a control process of transmitting a high frequency signal tothe piezoelectric motor 330 such that the piezoelectric motor 330generates piezoelectric ultrasound, the piezoelectric driving shaft 341connected to the piezoelectric motor 330 generates vibration accordingto the generated piezoelectric ultrasound, and the piezoelectricoperating unit 350 coupled to the piezoelectric driving shaft 341 movesalong the piezoelectric driving shaft 341 in accordance with thevibration of the piezoelectric driving shaft 341; and controlling thepiezoelectric operating unit 350 and the transducer 380 such that, everytime the light receiving element 358 receives light L from one of thelight emitting elements 225 a during movement of the piezoelectricoperating unit 350 along the piezoelectric driving shaft 341, thepiezoelectric operating unit 350 stops at a position where the lightreceiving element 358 receives light (one of the positions P1 to P8),and the transducer 380 is enabled to radiate ultrasound. The movementand stop of the piezoelectric operating unit 350 (at the same time,ultrasound radiation through the transducer 380) are repeated from theposition P1 to the position P8 (that is, the piezoelectric operatingunit 350 stops every time the light receiving element 358 receives lightfrom one of the light emitting elements 225 a during movement of thepiezoelectric operating unit 350, to allow radiation of ultrasoundthrough the transducer 380). Thus, thermal solidification points CA maybe formed at intervals of the distance d at the positions P1 to P8,respectively.

A double shot may proceed to again form thermal solidification points atthe positions where a series of thermal solidification points has beenformed, respectively. This double shot is the same as that of FIG. 10and, as such, no description thereof will be given.

Meanwhile, an HIFU device according to another embodiment of the presentinvention and a method for controlling a piezoelectric driving deviceused in the HIFU device will be described with reference to FIG. 12.

Similarly to the above-described embodiments, the embodiment illustratedin FIG. 12 provides a control method for more accurate and stablemovement of the piezoelectric operating unit capable of eliminating theproblem encountered in the embodiment illustrated in FIG. 9.

The embodiment of FIG. 12 relates to a configuration in which an opticalslit unit is provided at the piezoelectric driving device. In this case,the optical slit unit includes a sensor housing 228 extending along amovement path of the piezoelectric operating unit 350, light sources 227disposed in the sensor housing 228, and slits 229 formed at positions ofthe sensor housing 228 corresponding to positions P1 to P8, at which thetransducer 380 radiates ultrasound, respectively. In accordance with theconfiguration of the optical slit unit, light L from the light sources229 passes through associated ones of the slits 229.

Since the piezoelectric driving unit has a very small size, there may bea difficulty in providing light emitting elements at respectivepositions P1 to P8 due to the size of the light emitting elements. Sucha problem associated with size may be solved through a configuration inwhich light from one light source 227 passes through two or more slits229.

Light L passing through the plural slits 229 formed through the sensorhousing 228 in the above-described optical slit unit is received by alight receiving sensor 359 provided at an end of the piezoelectricoperating unit 350 (FIG. 12(a)).

FIG. 12(a) illustrates a configuration in which the light sources 227and the sensor housing 228 are provided at the PCB 220, and the slits229 formed through the sensor housing 228 correspond to ultrasoundirradiation positions, that is, positions P1 to P8, respectively.

In this embodiment, the controller 110 transmits a high frequency signalto the piezoelectric motor 330 and, as such, the piezoelectric motor 330generates piezoelectric ultrasound, the piezoelectric driving shaft 341connected to the piezoelectric motor 330 generates vibration accordingto the generated piezoelectric ultrasound, and the piezoelectricoperating unit 350 coupled to the piezoelectric driving shaft 341 movesalong the piezoelectric driving shaft 341 in accordance with thevibration of the piezoelectric driving shaft 341. During movement of thepiezoelectric operating unit 350, the light receiving sensor 359sequentially receives light L from the light sources 227 passing throughthe slits 229 of the sensor housing 228, as illustrated in FIG. 12(b).

When the light receiving sensor 359 receives light L, as describedabove, the controller 110 performs a control process for stopping thepiezoelectric operating unit 350 at a light receiving position (one ofthe positions P1 to P8), and enabling the transducer 380 to radiateultrasound. The movement and stop of the piezoelectric operating unit350 (at the same time, ultrasound radiation through the transducer 380)are repeated from the position P1 to the position P8 (that is, thepiezoelectric operating unit 350 stops every time when the lightreceiving element 359 receives light passing through one of the slits229 during movement of the piezoelectric operating unit 350, to allowradiation of ultrasound through the transducer 380). Thus, thermalsolidification points CA may be formed at intervals of the distance d atthe positions P1 to P8, respectively.

A double shot may proceed to again form thermal solidification points atthe positions where a series of thermal solidification points has beenformed, respectively. This double shot is the same as that of FIG. 10and, as such, no description thereof will be given.

As apparent from the above description, the present invention providesan HIFU device capable of achieving accurate and stable control as tomovement of a transducer and a treatment position while achieving agreat reduction in size by use of a piezoelectric driving deviceconfigured to have a compact size in accordance with a great reductionin the size of a handpiece, and a method for controlling thepiezoelectric driving device.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

What is claimed is:
 1. A method for controlling a piezoelectric drivingdevice to linearly move a transducer disposed in a cartridge of ahigh-intensity focused ultrasound handpiece, comprising: transmitting ahigh frequency signal to a piezoelectric motor, thereby causing thepiezoelectric motor to generate piezoelectric ultrasound, and causing apiezoelectric driving shaft connected to the piezoelectric motor togenerate vibration in accordance with the piezoelectric ultrasound;coupling a piezoelectric operating unit provided with the transducer tothe piezoelectric driving shaft, thereby causing the piezoelectricoperating unit to move along the piezoelectric driving shaft inaccordance with the vibration of the piezoelectric driving shaft; andpredetermining information as to positions, at which the transducerradiates ultrasound, and performing a control operation for stopping themovement of the piezoelectric operating unit along the piezoelectricdriving shaft when it is sensed that the piezoelectric operating unitreaches one of the predetermined position, and irradiating ultrasoundthrough the transducer.
 2. The method according to claim 1, wherein thecontrol operation for stopping the piezoelectric operating unit andirradiating ultrasound through the transducer comprises: previouslystoring, in association with a position sensor to sense a position ofthe piezoelectric operating unit, sensing values respectivelycorresponding to a plurality of positions, at which the transducerradiates ultrasound, stopping an operation of the piezoelectric motor tostop the piezoelectric operating unit and controlling the transducer toradiate ultrasound when a sensed value of the position sensor generatedduring movement of the piezoelectric operating unit is equal to one ofthe stored sensing values; and repeating the vibration generation, themovement of the piezoelectric operating unit along the piezoelectricdriving shaft, and the ultrasound irradiation through the transducer sothat the transducer sequentially radiates ultrasound at the positionsrespectively corresponding to the stored sensing values.
 3. The methodaccording to claim 1, wherein: a magnet is provided at an end of thepiezoelectric operating unit, and a plurality of Hall sensors isdisposed in the cartridge, to sense a magnetic field of the magnet; andthe control operation for stopping the piezoelectric operating unit andirradiating ultrasound through the transducer comprises: previouslystoring, in association with the Hall sensors, sensing valuesrespectively corresponding to a plurality of positions, at which thetransducer radiates ultrasound, stopping an operation of thepiezoelectric motor to stop the piezoelectric operating unit andcontrolling the transducer to radiate ultrasound when one of sensedvalues of the Hall sensors generated during movement of thepiezoelectric operating unit is equal to one of the stored sensingvalues; and repeating the vibration generation, the movement of thepiezoelectric operating unit along the piezoelectric driving shaft, andthe ultrasound irradiation through the transducer so that the transducersequentially radiates ultrasound at the positions respectivelycorresponding to the stored sensing values.
 4. The method according toclaim 1, further comprising: moving the piezoelectric operating unit fora predetermined time after irradiation of ultrasound through thetransducer at a last one of the predetermined positions; moving thepiezoelectric operating unit in an opposite direction; and performing acontrol operation for stopping the movement of the piezoelectricoperating unit along the piezoelectric driving shaft when it is sensedthat the piezoelectric operating unit reaches one of the predeterminedpositions, and irradiating ultrasound through the transducer, whereby adouble shot of ultrasound is carried out at a treatment area through thetransducer.
 5. A high-intensity focused ultrasound device forcontrolling a transducer disposed in a cartridge to linearly move and toradiate ultrasound for treatment, comprising: a piezoelectric drivingdevice comprising a piezoelectric motor disposed in the cartridge, togenerate piezoelectric ultrasound in accordance with a high frequencysignal, a piezoelectric driving shaft connected to the piezoelectricmotor, to generate vibration in accordance with the piezoelectricultrasound, and a piezoelectric operating unit provided with thetransducer and coupled to the piezoelectric driving shaft, to move alongthe piezoelectric driving shaft in accordance with the vibration of thepiezoelectric driving shaft; a position sensor for sensing a position ofthe piezoelectric operating unit; a high frequency generator forgenerating a high frequency signal enabling the piezoelectric motor togenerate piezoelectric ultrasound and a high frequency signal enablingthe transducer to radiate ultrasound for treatment; and a controller forpredetermining information as to positions, at which the transducerradiates ultrasound, and controlling the high frequency generatorperforming a control operation for stopping the movement of thepiezoelectric operating unit along the piezoelectric driving shaft whenit is sensed that the piezoelectric operating unit reaches one of thepredetermined positions, and irradiating ultrasound through thetransducer.
 6. The high-intensity focused ultrasound device according toclaim 5, wherein the controller previously stores, in association withthe position sensor, sensing values respectively corresponding to aplurality of positions, at which the transducer radiates ultrasound, andcontrols the high frequency generator such that the piezoelectric motorstops and the transducer radiates ultrasound when a sensed value of theposition sensor generated during movement of the piezoelectric operatingunit is equal to one of the stored sensing values.
 7. The high-intensityfocused ultrasound device according to claim 5, wherein: a magnet isprovided at an end of the piezoelectric operating unit, and a pluralityof Hall sensors is disposed at an area facing the magnet in a movementpath of the piezoelectric operating unit within the cartridge whilebeing spaced apart from one another by a predetermined distance; and thecontroller previously stores, in association with the Hall sensors,sensing values respectively corresponding to a plurality of positions,at which the transducer radiates ultrasound, stops an operation of thepiezoelectric motor to stop the piezoelectric operating unit andcontrols the transducer to radiate ultrasound when one of sensed valuesof the Hall sensors generated during movement of the piezoelectricoperating unit is equal to one of the stored sensing values.
 8. Thehigh-intensity focused ultrasound device according to claim 5, whereinthe position sensor comprises an optical sensor installed at one side ofthe piezoelectric driving device, to emit light toward the piezoelectricoperating unit, to receive the light reflected after being emitted, andto compare the received light with the emitted light, thereby sensingthe position of the piezoelectric operating unit.
 9. A high-intensityfocused ultrasound device for controlling a transducer disposed in acartridge to linearly move and to radiate ultrasound for treatment,comprising: a piezoelectric driving device comprising a piezoelectricmotor disposed in the cartridge, to generate piezoelectric ultrasound inaccordance with a high frequency signal, a piezoelectric driving shaftconnected to the piezoelectric motor, to generate vibration inaccordance with the piezoelectric ultrasound, and a piezoelectricoperating unit provided with the transducer and coupled to thepiezoelectric driving shaft, to move along the piezoelectric drivingshaft in accordance with the vibration of the piezoelectric drivingshaft; a high frequency generator for generating a high frequency signalenabling the piezoelectric motor to generate piezoelectric ultrasoundand a high frequency signal enabling the transducer to radiateultrasound for treatment; an optical element array unit comprising afirst optical element provided at one side of the piezoelectricoperating unit, the first optical element being one of a light emittingelement and a light receiving element, and an optical element arrayprovided at an area facing the first optical element, the opticalelement array comprising a plurality of second optical elements eachbeing the other of the light emitting element and the light receivingelement, so that light reception is achieved between the first opticalelement and the second optical elements during movement of thepiezoelectric operating unit along the piezoelectric driving shaft; anda controller for controlling the high frequency generator to enable thepiezoelectric operating unit to move in accordance with vibrationgenerated by the piezoelectric ultrasound and to enable the transducerto radiate ultrasound, stopping the piezoelectric operating unit whenthe light reception is achieved by the optical element array device, andirradiating ultrasound through the transducer.